The major objective of this research project is to determine basic mechanisms of experimental ocular inflammation, particularly those changes occuring in blood vessels, and how they affect the inflammatory process. The project is in three parts. 1) The factors responsible for the prolongation of the acute inflammatory process will be investigated in the ocular response to circulating bacterial endotoxin. These factors will be evaluated by determination of the ocular accumulation of labeled albumin and histopathologic study following the intravenous injection of bacterial endotoxin. The complement system will be studied in rabbits depleted of C'3 by cobra venom factor and the kinin system will be examined following Trasylol, and the use of other kininogenase and kininase inhibitors. In addition, endothelial fibrinolysin activator will be investigated by the fibrin slide techniques in ocular blood vessels following intravenous endotoxin. The possible direct endothelial damage produced by endotoxin will be studied with tritium-labeled endotoxin and microradio-autography. 2) The potential role of some blood clotting factors as primary participants in the inflammatory process will be examined. Ocular tissues will be examined for the presence of Hageman Factor, thrombin and fibrinogen will be prepared from rabbit, injected into various ocular compartments, and their effects noted by clinical examination, I125-HSA accumulation, and histopathologic study. 3) The possible role of thrombosis of the micro -circulation in peripheral corneal disease will be examined by studying a modified local Shwartzman reaction in the cornea. The effect of disseminated intravascular clotting on ocular blood vessels will be studied in the rabbit, cat and monkey. BIBLIOGRAPHIC REFERENCES: Howes, E.L., Jr., and McKay, D.G.: Effects of circulating immune complexes on ocular vascular permeability, ARCH OPHTHAL 93:365-370, 1975. Kalowski, S., Howes, E.L., Jr., Margaretten, W. and McKay, D.C.: Effect of intravascular clotting on the activation of the complement system. The role of the platelet. AMER J OF PATH. 78:525-536,1975.